Insert four non-rechargeable AA batteries into the flash unit's battery port. Battery voltage is one of the main causes for the overheating of the SB-900. Rechargeable batteries have a voltage of 1.2V while non-rechargeable have a voltage of 1.5V. The lower voltage of the rechargeable batteries makes them work harder to recycle the flash, resulting in premature exhaustion and overheating.
Attachable flash units that overheat too easily can be a burden for the frugal photographer. Constant overheating is bad for the unit itself and the batteries that power it, and the resulting flash failure can ruin chance photographic opportunities. The Nikon SB-900 is a very competent flash but it can fall victim to overheating if its user does not take a few precautions. The steps below are for the SB-900 model but may be applicable to similar Nikon flash units.
Things You'll Need
- Nikon SB-900 flash (or similar model)
- Four non-rechargeable AA batteries
Avoid using the Auto Area Auto-Focus (AF) option on the flash unit. The SB-900 has three AF illuminators located within the red plate on the front of the unit. These measure the amount of available light falling on the in-focus subject so it knows how much light to emit when fired. The Auto Area AF mode uses all three of these illuminators, which can exhaust the batteries if used frequently in rapid succession. Switch to Single Point or Dynamic Area AF instead, as these options do not use all three illuminators.
Learn to use your flash unit with its available manual modes. Setting your flash to any combination of Auto mode requires a quick pre-flash which helps determine how much light is available and how much will be needed for proper exposure. Using Auto modes frequently drains the batteries very quickly. If you must use Auto mode for unpredictable conditions, try to space out your flash firings to allow the batteries to cool.
Shoot with larger aperture openings (f1.2 down to f8). Small aperture openings (f11 down to f22) require larger outputs of light to provide the correct amount of exposure. If you are shooting at a rapid pace, the amount of power required to light the subject will quickly tax the batteries and cause the unit to overheat.
Move close to your subject when firing your flash. The SB-900 is usable with telephoto lenses up to 200mm, but the amount of energy required to cast light onto a distant subject is high. Depending on how much recycling time you can afford, use your flash unit with a zoom or long telephoto lens sparingly.
Tips & Warnings
- The batteries you choose are the most important part of preventing instances of overheating. Choose 1.5V batteries if none of the other above steps is viable.
- Take your flash to a reputable camera repair service if overheating continues.
- If your flash unit becomes extremely hot to the touch, stop using it and allow it to cool before removing it from your camera. It can become an electrical hazard.
- Photo Credit old camera 2 image by James Lemmon from Fotolia.com
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